A grinding device such as a surface grinding machine or a cylindrical grinding machine includes a rotary spindle, chuck mounted on the front end of the spindle for fixing a workpiece, a rotary grinder shaft having a grinder head, and a grinder mounted on the grinder head. By moving the spindle and the grinder shaft in the axial direction of the spindle or in a direction perpendicular to the axis of the spindle, the workpiece is ground by the grinder.
Some of such grinding devices include a dresser which can dress the grinder without the need to dismount the grinder from the grinder head (see e.g. JP Patent Publication 8-229815A and JP Patent Publication 2006-95663A).
The grinding device disclosed in JP Patent Publication 8-229815A includes a grinder shaft carrying a grinder, and a dresser head support base having a pivotable pivot shaft extending parallel to the grinder shaft. The dresser head support base further includes a spindle extending parallel to the pivot shaft to which a dressing member as a dresser tool is detachably mounted. By pivoting the pivot shaft, the dressing member is pressed against the grinder. The dresser head support base carries a motor whose rotation is transmitted to the spindle through a gear transmission mechanism.
The grinding device disclosed in JP Patent Publication 2006-95663A includes a main spindle head to which both a workpiece and a dresser tool are attached. In particular, after dismounting the workpiece, the dresser tool is attached to the main spindle head to dress the grinder mounted on the grinder head.
The grinding device disclosed in JP Patent Publication 8-229815A needs the dresser head support base including the pivot shaft, the motor for rotating the spindle carrying the dressing member, and the gear transmission mechanism. Thus, the dressing mechanism is large in size and complicated in structure, so that its manufacturing cost is high. The dressing mechanism of the grinding device disclosed in JP Patent Publication 2006-95663A is simple in structure. But it is necessary to mount the dresser tool on the main spindle head after dismounting the workpiece every time the grinder is dressed, which is troublesome.